粉末丁腈橡胶改性SMC的研究

采用粉末丁腈橡胶(PNBR)和PNBR/聚苯乙烯(PS)体系改性SMC复合材料,研究了玻纤、CaCO3、PNBR和PNBR/PS体系对SMC的收缩率、力学性能和表面质量的影响。结果表明:玻纤和CaCO3能降低SMC的收缩率,但效果较小,CaCO3对表面质量有积极作用,其最佳质量分数为41.5%;PNBR的加入显著地降低了SMC的收缩率,同时提高了韧性,当其质量分数为5.2%时,收缩率达到0.05%以下;PNBR/PS体系的抗收缩效果优于PNBR,当PNBR/PS质量比为1∶2时,能够实现零收缩,而且改性SMC具有优良的力学性能和表面质量。     

SMC/BMC用低收缩添加剂的研究进展

本文介绍了SMC/BMC用低收缩添加剂(LPA)的发展历程,并从微观相结构方面阐释了PE、PSt、PVAc、及SBS类LPA的性能差异.随后介绍了一些LPA的合成路线,着重详述了一些LPA 合成方面的最新进展,如高抗冲PS、改性PVAc类LPA的合成,并由此得出关于LPA研究的路线、方法等方面的结论.     

低收缩/低波纹添加剂对SMC力学性能的影响

本文主要研究了不同品种的LSA/LPA和不同用量的LSA/LPA对SMC力学性能及收缩率的影响。研究表明,不同品种的LSA/LPA由于极性不同,其控制收缩机理也略有不同,使得其对SMC力学性能及收缩率的影响也不同。其中,PS和PMMA强度开始快速下降的拐点在65∶35~61∶39(UP:LSA/LPA)之间,而PVAc在59∶41以上。综合考虑力学性能和收缩控制的平衡,本研究得到了不同品种LSA/LPA的最佳用量范围,实现了配方设计的优化。     

PP/PS合金的研制

研究了苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)对聚丙烯／聚苯乙烯(PP／PS)合金的形态结构和力学性能的影响。结果表明：SBS是PP／PS合金良好的增容剂，只要体系中加入质量分数少于10％的SBS，就能很大程度提高合金的冲击强度，改善体系的相形态结构；当m(PP)：m(PS)=75：25时，与简单物理共混的PP／PS相比。其冲击强度由4．53kJ/m2增加到65．36kJ／m^2；同时随PS质量分数的增加，体系的刚性也增强。     

PP/PS/SBS共混物的性能研究

通过添加聚苯乙烯(PS)、热塑性弹性体苯乙烯-丁二烯-苯乙烯共聚物(SBS),以改善聚丙烯(PP)的性能。先采用熔融法制备PP/PS共混物,在确定PP,PS最佳配比的基础上,再添加SBS制备PP/PS/SBS共混物,确定了PP,PS及SBS的最佳配比。研究了PP/PS,PP/PS/SBS共混物的力学性能、热性能及熔体流动行为。结果表明,当PP与PS的质量比为70∶30时,PP/PS共混物的性能最好,其拉伸强度为28.5 MPa,拉伸弹性模量为1 214 MPa,弯曲弹性模量为1 752 MPa,冲击强度为14.0 kJ/m2,断裂应变为130%,维卡软化温度为143.9℃。当PP,PS及SBS的质量比为70∶30∶10时,PP/PS/SBS共混物的性能最好,其拉伸强度为23.2 MPa,拉伸弹性模量1 040 MPa,断裂应变为260%,冲击强度为18.0 kJ/m2,弯曲强度为36.5 MPa,弯曲弹性模量为1 297 MPa,定挠度弯曲应力为36.1 MPa,弯曲破坏应力为36.5 MPa,熔体流动速率为8.94 g/(10 min),维卡软化温度为139.0℃。     

聚苯乙烯改性沥青高温性能研究

通过反应共混技术制备了聚苯乙烯（PS）/苯乙烯-丁二烯-苯乙烯共聚物（SBS）改性沥青,研究了 PS 用量、反应剂硫磺（sulfur）对沥青高温贮存稳定性、黏度-温度特性和动态力学性能的影响。结果表明:通过反应共混改性所得到的改性沥青在高温贮存时,当 PS/SBS 不大于1/1时贮存样品上下层软化点差值小于2.5℃,贮存稳定性能得到了明显改善。对于沥青/PS/SBS/Sulfur 为100/3/3/0.15的体系,沥青的黏流活化能（Eη）从65kJ/mol 降低到了52.8kJ/mol;同时显著提高了沥青的高温复数模量和弹性,损耗角正切值（tanδ）在30～100℃范围内的变化小于10。     

SBS/PS/剑麻纤维复合材料的制备及性能研究

通过熔融共混的方法制备了丁苯热塑性弹性体/聚苯乙烯/剑麻纤维(SBS/PS/SF)复合材料。采用SBS/PS=70/30的配比,通过改变剑麻纤维用量,研究SBS/PS/SF复合材料的力学性能、热性能及熔体流动速率。结果表明:随着剑麻纤维用量的增加,SBS/PS/SF复合材料的弹性模量和弯曲强度都有所增加;熔体流动速率呈减小趋势;拉伸强度、断裂应变、屈服应变和冲击强度先上升后下降;SBS/PS/SF复合材料的维卡软化点随着剑麻纤维的加入也有着不同程度的下降。     

拉伸作用对剑麻纤维增强SBS/PS复合材料的影响

以丁苯热塑性弹性体(SBS)为研究对象,通过添加聚苯乙烯(PS)、剑麻纤维(SF),采用熔融共混方法制备SBS/PS/SF复合材料,研究了复合材料在拉伸作用下的应力松弛、力学性能及结构变化规律。结果表明:随着SF用量、拉伸应变和加载速率的增加,SBS/PS/SF复合材料的应力均增加;SBS/PS/SF复合材料经拉伸应变作用后的拉伸强度先升后降,且比未施加的高。SBS/PS/SF复合材料受到较低应变作用时,SF分布均匀,排列取向较好,界面结合良好;当SF用量较高且施加应变较大时,SF容易发生剥出和断裂。     

PS／SBS共混体系的性能研究

本文研究了SBS改性PS，同时对填充了滑石粉和经过处理的滑石粉的共混体系进行了实验。结果表明：在PS树脂中加入一定量的SBS可以提高冲击强度和断裂伸长率，但弯曲强度、拉伸强度和熔体流动速率等性能下降。滑石粉的加入可以明显提高共混体系的弯曲强度，用1％的硬脂酸处理过的滑石粉比未处理的滑石粉对PS／SBS共混体系的改性效果要好。     

热塑性弹性体改性聚苯乙烯复合材料的制备及力学性能研究

选用热塑性弹性体苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)作为聚苯乙烯(PS)改性剂,制备PS/SBS共混复合材料,对其拉伸性能、弯曲性能、冲击性能、熔体流动速率、热稳定性及耐热性能进行测试,并对断面形貌进行表征。结果表明:SBS与PS具有很好的相容性。SBS添加量从0增加至20%,PS/SBS复合材料的冲击强度、熔体流动速率、峰值温度、维卡软化温度分别从13.08 kJ/m2、9.0 g/10min、403℃、84℃增加至51 kJ/m2、11.9 g/10min、420℃、89.3℃。SBS的添加有效提高复合材料的韧性及热学性能,但降低复合材料的拉伸性能。当PS/SBS质量比为92∶8,改性PS复合材料的拉伸性能与纯PS相比减弱幅度较小,且PS/SBS的冲击强度、熔体流动性、热稳定性、耐热性、相容性均显著提高,复合材料性能最佳。     

Thermal and mechanical properties of microcellular thermoplastic SBS/PS/SBR blend: effect of crosslinking

This study investigates the effect of peroxide crosslinking on the structure and mechanical properties for SBS/PS/SBR foams composed of polystyrene (PS), poly(styrene-b-butadiene) diblock copolymer (SBR-1502), and poly(styrene-b-butadiene-b-styrene) triblock copolymer (SBS). The cell size and its distribution of SBS/PS/SBR foams were investigated by SEM images, showing the smaller and denser of hollow cells for the SBS/PS/SBR foam containing the higher concentration of DCP (dicumyl peroxide). As expected, the density of the SBS/PS/SBR foams increases with increasing the content of DCP. The high density of polymeric foams exhibits the high mechanical properties such as hardness, shrinkage, tensile strength, tear strength, elongation at break, and compression set.     

废报纸粉填充聚丙烯材料的研究

本文介绍废报纸粉填充聚丙烯（ＰＰ）的研制。通过在体系中加入高分子偶联剂马来酸酐（ＭＡＨ）接枝ＰＰ（ＭＡＰＰ）来改善纸粉与ＰＰ基体的相容性，并针对纸粉填充后材料变脆的问题，用乙丙橡胶（ＥＰＤＭ）和乙烯醋酸乙烯共聚物（ＥＶＡ）对材料进行增韧，均取得显著的效果。所制材料的纸粉填充量（质量分数）可高达５０％～６０％，价廉、质轻、其主要性能好于桑塔纳轿车用木粉填充ＰＰ板，可望有较好的应用前景。当纸粉填充量（质量分数）为４０％～５０％时，主要性能：弯曲强度６９．０１～７４．８３ＭＰａ，杨氏弯曲模量２６４０～２９９６ＭＰａ，冲击强度１３．２５～１３．５０ｋＪ／ｍ２。     

Morphology and mechanical properties of styrene-butadiene-styrene/polystyrene semi-interpenetrating polymer networks and their blends

SBS/PS semi-interpenetrating polymer networks (semi-IPNS) were synthesized by swelling a linear styrene-butadiene-styrene (SBS) triblock copolymer (SBS, Kraton 1102) with styrene monomer plus benzoin as photoinitiator and divinylbenzene as cross-linking agent. Polyblends were prepared by solution casting of SBS and polystyrene (PS) in their ideal solvents. Measurements were made for viscoelastic properties and mechanical properties of phase-separated polymer alloy (including SBS copolymers Kraton 4122), semi-IPNs and polyblends of several SBS and PS, with the same total PS content (48% PS). The dynamic mechanical behaviour shows distinct transitions for each polymer, in agreement with electron microscopy results that SBS/PS polymer alloy forms two phases; however, the phase domains were finer in the semi-IPNs than in SBS triblock copolymer and in polyblends of the corresponding polymers. Stress-strain data show that semi-IPNs exhibit higher tensile strength and modulus than the other two corresponding polymer alloys. A master curve was plotted to illustrate the stress relaxation behaviour of samples at higher temperatures. Our results also reveal that semi-IPNs have much better high-temperature mechanical strength.     

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

The compatibilizing effect of the triblock copolymer poly(styrene-b-butadiene-b-styrene) (SBS) on the morphology and mechanical properties of immiscible polypropylene/polystyrene (PP/PS) blends were studied. Blends with three different weight ratios of PP and PS were prepared and three different concentrations of SBS were used for investigations of its compatibilizing effects. Scanning electron microscopy (SEM) showed that SBS reduced the diameter of the PS-dispersed particles as well as improved the adhesion between the matrix and the dispersed phase. Transmission electron microscopy (TEM) revealed that in the PP matrix dispersed particles were complex “honeycomblike” aggregates of PS particles enveloped and joined together with the SBS compatibilizer. Wide-angle X-ray diffraction (WAXD) analysis showed that the degree of crystallinity of PP/PS/SBS slightly exceeded the values given by the addition rule. At the same time, addition of SBS to pure PP and to PP/PS blends changed the orientation parameters A₁₁₀ and C significantly, indicating an obvious SBS influence on the crystallization process in the PP matrix. SBS interactions with PP and PS influenced the mechanical properties of the compatibilized PP/PS/SBS blends. Addition of SBS decreased the yield stress and the Young's modulus and improved the elongation at yield as well as the notched impact strength in comparison to the binary PP/PS blends. Some theoretical models for the determination of the Young's modulus of binary PP/PS blends were used for comparison with the experimental results. The experimental line was closest to the series model line. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 2625–2639, 1998     

填料改性SBS热塑性弹性体的研究

研究了不同填料以及改变填料用量、补强体系分别对热塑性弹性体ＳＢＳ各种性能的影响，并测定了最佳配方的挤出性能及工艺条件。结果表明，白炭黑的适量加入对ＳＢＳ的撕裂强度有显著提高，适量活性钙可提高ＳＢＳ的拉伸强度和撕裂强度，聚烯烃填料作为填充剂可以降低胶料的成本。该配方主要适用鞋底料的研究。     

Effects of the molecular structure of impact modifier and compatibilizer on the toughening of PBT/SBS/PS‐GMA blends

This work aims at studying the toughening process of poly(butylene terephthalate) (PBT) through its blends with styrene‐butadiene‐styrene block copolymers (SBS), in the presence of poly(styrene‐ran‐glicydil methacrylate) (PS‐GMA) as reactive compatibilizer. High values of impact strength were attained for PBT/SBS blends without the compatibilizer; however, this improvement is achieved for blends with SBS having similar viscosity compared to PBT, at high SBS content (40 wt %) and for blends prepared under specific processing conditions. The efficiency of the in situ compatibilization of PBT/SBS blends by PS‐GMA was found to be strongly dependent on the SBS and PS‐GMA molecular characteristics. Better compatibilizing results were observed through fine phase morphologies and lower ductile to brittle transition temperatures (DBTT) as the interfacial interaction and stability of the in situ formed compatibilizer are maximized, that is, when the miscibility between SBS and PS‐GMA and reaction degree between PBT and PS‐GMA are maximized. For the PBT/SBS/PS‐GMA blends under study, this was found when it is used the SBS with higher polystyrene content (38 wt %) and with longer PS blocks (M_w = 20,000 g mol^?1) and also the PS‐GMA with moderate GMA contents (4 wt %) and with molecular weight similar to the critical one for PS entanglements (M_c = 35,000 g mol^?1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5795–5807, 2006     

Study of PS/SBS/nano-CaCO3 blends

Abstract

The effect of SBS and nano-CaCO₃ on the mechanical properties of PS blends was studied, and their morphologies were characterised by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Izod impact strengths of notched samples of PS/SBS/CaCO₃ blends with nanometre particles of nano-CaCO₃ and SBS are higher than those of PS and PS/SBS blends with the same content of SBS, and the tensile strengths are higher than those of PS/SBS blends. The inclusion of nano-CaCO₃ within the dispersed phase of SBS enlarges the volume of the domains of SBS, which increases the toughness of the ternary blends (PS/SBS/CaCO₃). The mass ratio of SBS/CaCO ₃ plays an important role in the properties of the ternary blends because it affects the concentration of SBS in these blends, the dispersion of nano-CaCO₃ and the morphology of the ternary blends.     

Effect of nanoclay on mechanical and thermal properties of triblock SBS (styrene–butadiene–styrene) and its binary blend nanocomposites: comparison between polyethylene and polystyrene

ABSTRACT

In this study, the effect of organo-modified nanoclay (OMMT) on the mechanical and thermal properties of SBS and its blend with low-density polyethylene (LDPE) and polystyrene was investigated. The effect of nanoclay content in the presence of LDPE or PS on the final properties of SBS was studied by tensile tester, dynamic mechanical thermal analysis (DMTA), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Addition of nanoclay affected the mechanical and rheological properties. From X-ray and DMTA results, it was found that due to more affinity between the nanoparticles and the SBS/PE blend, the 2 theta characteristic peak of nanoclay shifted to lower angles. SEM studies showed better dispersion and lower inter-particle distance of nanoparticles in SBS/PE composites in comparison with SBS/PS and SBS composites, confirming the XRD and DMTA results. It can be concluded that nanoclay acts as a compatibilizer in the SBS/LLDPE blend. TGA studies showed higher stability of SBS/PS composites compared to SBS and SBS/PE ones.     

Near-surface morphology effect on tack behavior of poly(styrene-b-butadiene-b-styrene) triblock copolymer/rosin films

The correlation between near-surface morphology and tack behavior of poly(styrene-b-butadiene-b-styrene) triblock copolymer (SBS)/rosin ester films was investigated using probe tack tests, transmission electron microscopy and small-angle X-ray scattering. The SBS/rosin films with rosin composition between 10 and 20 wt% rosin, prepared by slow evaporation of toluene during solvent casting, exhibited uniform near-surface morphology of lamellae oriented parallel to the surface. However, due to the limited solubility of rosin in the PS domains, the rosin started to phase-separate from the PS domains at 15 wt%, and formed fully separated micron-sized domains above 20 wt% rosin. The probe tack force of the SBS/rosin films increased steadily when the near-surface domain orientation changed from perpendicular cylinder to parallel lamellae on addition of rosin. Specifically, for a given lamellar morphology and surface orientation, macrophase separation of rosin plays a critical role in determining the tack properties of SBS/rosin films.